The present invention relates to a buckle for seatbelts normally used for child seats and the like, particularly for chairs which attach to car seats, where safety regulations require such seatbelts to have three straps which are suitably attached to the seat and meet at a common point passing through a buckle, which is also common to the three straps.
The object of the invention is to obtain a buckle of the aforementioned type which is structurally simple and has an ideal safety performance, so that the mutual attachment between the three parts of which it consists takes place in two points which are considerably separated from each other, as well as defining both a front anchoring point and a side anchoring point.
Safety buckles of the aforementioned type generally comprise a single-piece base provided on one of its ends with a groove or ring for attaching one of the straps which form the safety belt, and in addition defining a housing for a pair of headers which are in turn provided with corresponding rings for the other two straps, which rings are also provided with sectors which attach to each other by a male-female coupling system and which are jointly inserted in the housing of the base, and which base is provided with means for retaining or locking the former and which are released by pressing a button.
In general, means for locking the two headers within the base comprise an elastically deformable tab which ends in a saw-tooth shape which in turn acts on one of the housings, so that the locking means are secured by a simple insertion of the headers in the base, while unlocking takes place by operating a button.
These buckles are further similar in that they comprise a single locking tooth which acts on one point of one of the headers, and most are also similar in that the button acts against the elastic deformation of the locking tab, resulting in a problem which entails two aspects: the locking is not as secure as would be ideal; and the lifetime of the buckle is limited by the risk of the deformable locking tab breaking, due to crystallisation or whichever reason.
The safety buckle disclosed by the invention solves the aforementioned problems in a fully satisfactory manner.
For this purpose, more specifically and according to a basic structure of a conventional safety lock which comprises a base provided with a housing for coupling of the corresponding sector of two complementary headers, which header sectors housed in the base interlock by means of a matching system, said buckle is characterised by a special configuration of the locking/release button which together with a complementary configuration of the headers allows attachment of these headers, as mentioned before, to take place in two points which are significantly separated from the buckle, with the ensuing safety, and with the button moving against a spring with a useful lifetime which for practical purposes is indefinite.
More specifically, said button can move transversely also against the spring, and through guides made for such purpose in the base, and is further provided with two locking teeth, one lateral and one frontal and, in addition, in its matching coupling sector, whose width is practically identical to the base housing, incorporates a guide in the form of a bent groove for coupling the frontal tooth and a side notch is for coupling the also lateral tooth of the button, and in addition said guide and notch have inclined access ramps to the final locking position of the teeth, causing an automatic transverse displacement of the button in the coupling operation of the headers and the base, acting against the opposition of the aforementioned lateral spring by simple frontal pressure of the headers against the base.
Additionally, and as is conventional, the buckle further incorporates a second spring here placed axially on the base for the obvious purpose of pushing both headers out when they are released by a lateral pressure on the button.